First I created it using Cylindrical Coordinates with K3dSurf under parametric tab and when I was pleased with it then I mapped it back to an Cartesian Coordinates using a little math from a Calculus book I had lying around.
sqrt(x ^ 2 + y ^ 2 + z ^ 2) - atan(y / x) - log(abs(cos(z)))
-4 <= x <= 4
-4 <= y <= 4
-4 <= z <= 4